We are requesting funds to purchase an Agilent 5977B gas chromatograph/mass spectrometer (GC/MSD) to measure the level of oxidative stress in tissues. Research over the past two decades implicates increased oxidative stress as an important factor in the etiology of many of the major diseases that affect our Veteran population, e.g., cancer, liver disease, atherosclerosis, neurodegeneration (e.g., Alzheimer?s disease, Parkinson?s disease, and amyotrophic lateral sclerosis), and type 2 diabetes. Thus, an accurate assay for assessing the level of oxidative stress biological samples is critical in determining the role of oxidative stress in these diseases, which will be important in the eventual treatment and prevention of these diseases. Measures of oxidative damage to lipid, DNA, and protein have all been used to measure oxidative stress, and Drs. Van Remmen and Richardson at the Oklahoma City VA Health Care System (OKCVA HCS) have pioneered the development of many of these assays. Currently, there are a number of commercial kits to measure various types of oxidative damage. While these kits are relatively inexpensive and do not require major instrumentation, they have a low sensitivity (i.e., they are unable to pick up changes in the levels of oxidative damage in mildly stressed cells/tissues), and researchers often encounter the problem of reproducibility when using these kits, i.e., data often vary from laboratory to laboratory. Dr. Van Remmen has found that the most sensitive and reproducible method to measure oxidative stress in biological samples is the measurement of oxidative damage to lipids as measured by the level of isoprostanes. The formation of isoprostanes is an excellent marker of oxidative stress because isoprostanes can be measured with precision down to the picomolar level; they are relatively stable; and they do not exhibit diurnal variations. The Agilent 5977B GC/MSD will be used to measure isoprostanes in the Integrative Redox Biology Core directed by Dr. Van Remmen at the OKCVA HCS. It will replace the current 12-year old GC/MS, which was purchased by the VA in 2003 and has been used by Dr. Remmen as part of VA and NIH funded Centers over the past decade. The Agilent 5977B GC/MSD will provide VA investigators across the country with the most sensitive, accurate, and reproducible measurement isoprostanes in tissues. Because this assay requires dedicated personal and state-of-the-art instrumentation, it is impossible for investigators to easily adapt this technology to their laboratories. The fact that no other VA Medical Center or research institution routinely provides this assay to researchers, makes this service provided by the Integrative Redox Biology Core at OKCVA HCS a unique and valuable resource for the scientific community. The Agilent 5977B GC/MSD System we are requesting not only gives us a new, reliable GC/MS but several improvements have dramatically increased the sensitivity of the instrument, resulting in detection limits as low as 1.5 fg. As a result, the sensitivity of the Agilent 5977B GC/MSD system is 10-fold greater than past GC/MS systems. Over the past decade, there has been a considerable demand for this service provided by Cores directed by Dr. Van Remmen in VA- and NIH-funded Centers. We envision that the demand for this service will continue, e.g., 8 VA investigators at OKCVA HCS and at other VA Medical centers across the United States have provided letters expressing their interest in using the Agilent 5977B GC/MSD in the Integrated Redox Biology Core in their VA funded research. Dr. Van Remmen will lead the Integrated Redox Biology Core, which is part of an NIH-funded Oklahoma Nathan Shock Aging Center. She has 12 years of experience measuring isoprostanes in tissues and operating and maintaining a similar GC/MSD. The Oklahoma Shock Center will provide funds for a dedicated staff member to process the tissues and the operate and maintain the GC/MS. In addition, a fee-for-service schedule is in place to pay for supplies and the service contract for the Agilent 5977B GC/MSD.